# MediaPipe subgraph that calculates hand ROI from palm detection.

type: "PalmDetectionDetectionToRoi"

# Palm detection. (Detection)
input_stream: "DETECTION:detection"
# Frame size. (std::pair<int, int>)
input_stream: "IMAGE_SIZE:image_size"

# ROI (region of interest) according to landmarks, represented as normalized
# rect. (NormalizedRect)
output_stream: "ROI:roi"

# Converts results of palm detection into a rectangle (normalized by image size)
# that encloses the palm and is rotated such that the line connecting center of
# the wrist and MCP of the middle finger is aligned with the Y-axis of the
# rectangle.
node {
  calculator: "DetectionsToRectsCalculator"
  input_stream: "DETECTION:detection"
  input_stream: "IMAGE_SIZE:image_size"
  output_stream: "NORM_RECT:raw_roi"
  options: {
    [mediapipe.DetectionsToRectsCalculatorOptions.ext] {
      rotation_vector_start_keypoint_index: 0  # Center of wrist.
      rotation_vector_end_keypoint_index: 2  # MCP of middle finger.
      rotation_vector_target_angle_degrees: 90
    }
  }
}

# Expands and shifts the rectangle that contains the palm so that it's likely
# to cover the entire hand.
node {
  calculator: "RectTransformationCalculator"
  input_stream: "NORM_RECT:raw_roi"
  input_stream: "IMAGE_SIZE:image_size"
  output_stream: "roi"
  options: {
    [mediapipe.RectTransformationCalculatorOptions.ext] {
      scale_x: 2.6
      scale_y: 2.6
      shift_y: -0.5
      square_long: true
    }
  }
}